1. Technical Field
The present invention relates to an image display device.
2. Related Art
JP-A-2000-312319 (Patent Document 1) discloses a head-mounted display that detects, using an attitude sensor attached thereto, an angle at which the head-mounted display is inclined from a horizontal level, and rotates a display image to thereby allow a viewer to view an image that is kept horizontal.
As systems for preventing a blurring of vision caused by the movement of the human head, there are reflex eye movements that are called vestibulo-ocular reflex and optokinetic eye movement. The vestibulo-ocular reflex is a reflex in which the semicircular canals of the inner ear detect head rotation and cause the eyeballs to rotate in a direction opposite to the rotation of the head. The optokinetic eye movement responds slower than the vestibulo-ocular reflex, in which the visual system detects the entire movement of vision and causes the eyeballs to rotate in the same direction as that of the movement. The vestibulo-ocular reflex and the optokinetic eye movement cooperate together to react to head rotation at various speeds, thereby preventing a blurring of vision.
Hence, even when rotation correction of the display image is performed according to the rotation angle of the head as in the invention disclosed in Patent Document 1, there is a problem that an image that is kept accurately horizontal cannot be displayed on the viewer's eyes due to the optokinetic eye movement.